Fuel heating device for internal combustion engines



June 4, 1968 SHIGEICHI KAMIJO 3,386,426

FUEL HEATING DEVICE FOR INTERNAL COMBUSTION ENGI NES Filed May 4, 1966 Fig. I.

m a- 2 spu l INVENTOR$ United States Patent 3,386,426 FUEL HEATING DEVICE FOR INTERNAL COMBUSTION ENGINES Shigeichi Kamig'o, Tokyo, Japan, assignor to Takayuki T akahashi and Shigeichi Kamijo, Tokyo, Japan Filed May 4, 1966, Ser. No. 547,548 1 Claim. (Cl. 123-119) ABSTRACT OF THE DISCLOSURE A preheater for fuel fed to an internal combustion engine wherein the heat is obtained from exhaust gas, including a spring biased valve closed during low speed and open during high speed.

This invention relates to a fuel heating device for internal combustion engines and more particularly to an improved fuel heating device connected between a carburettor and "an internal combustion engine for a motor car, for example, to heat the fuel, or the mixture of fuel and air by the heat of exhaust gas.

With the conventional construction of the intake manifold of an engine and carburettor it is difficult to use kerosene as the fuel. More specifically, with regard to the distillation character of fuels, the initial point of ordinary gasoline is about C. and its end point is about 200 C., whereas the initial point of kerosene is about 140 and the end point is about 250 C. As is well known in the art, gasoline in the form of mist is mixed with suction air by the action of the carburettor and is then introduced into cylinders of the internal cumbustion engine. With the conventional fuel heating device, at the initial stage of compression, only a portion of fuel mist is evaporated and the remaining portion is evaporated by the heat of compression and the like until the final stage of compression is reached at which time the evaporated fuel is ignited. By this reason when utilizing kerosene in lieu of gasoline, substantially no fuel is evaporated at the initial stage of compression and even at the final stage there remains a large quantity of non-evaporated fuel with the result that prefect combustion can not be expected even when it is ignited.

Accordingly, it is the principal object of this invention to provide a new and improved fuel heating device for internal combustion engines which permits utilization of inexpensive liquid fuel such as kerosene.

A further object of this invention is to provide a novel fuel heating device which can prevent overheating of the fuel at high speed running.

A still further object of this invention is to provide a novel fuel heating device for internal combustion engines which can be readily incorporated therewith.

Yet another object of this invention is to provide a novel fuel heating device for internal combustion engines which enables the engines to exhibit larger output with economical fuel consumption.

In accordance with this invention these and further objects can be attained by providing a fuel heating device for internal combustion engines, comprising a hollow box shaped heater body, a mixed gas conduit contained in said heater body, and at least one suction port for said conduit which is opened through the upper wall of the heater body at the central portion thereof but at a position closer to the rear wall of the heater body, said suction port being adapted to be connected to a carburettor to introduce a mixture of air and fuel or mixed gas into said conduit, said conduit extending on both sides of 'said suction port and being bent towards the front wall of said heater body. Said fuel heater further comprises mixed gas outlet ports at the opposite ends of "ice said conduit and extending through the front wall to supply said mixed gas to the engine connected to the front wall, an exhaust gas passage extending in the heater body between the inner Wall thereof and said mixed gas conduit, an exhaust gas inlet opening provided for the exhaust gas passage, said exhaust gas inlet opening extending through said front wall at a level below said mixed gas outlet opening, a discharge port for said exhaust gas passage extending through the bottom wall of the heater body at a position just below said mixed gas suction port and an exhaust gas turbulator in said gas passage.

In a preferred embodiment of this invention a plurality of mixed gas suction ports are provided for the mixed gas conduit transversely of the upper wall of the heater body at positions closer to the rear Wall thereof and an external air suction valve is provided for the mixed gas conduit which is opened in responseto the high speed running condition of the engine to introduce cool air into said conduit to prevent the mixed gas from being overheated.

With the heating device constructed according to this invention, the temperature of the intake manifold is elevated to more than about C. by the waste heat of the exhaust gas so that not only a portion of the fuel i.e. kerosene vaporizes in the intake manifold but also the initial temperature of compression becomes sufficiently high. As a result the temperature at the final stage of compression is greatly increased to ensure substantially perfect evaporation of the liquid fuel and hence its perfect combustion.

While octane number of kerosene is considerably lower than that of gasoline it is possible to prevent the danger of knocking or detonation by adding thereto a suitable kerosene distillate of high octane number or by adding a suitable antiknock agent or agent effective to increase octane number so as to increase the overall octane number to more than about 60 while at the same time by somewhat decreasing the compression ratio of the engine.

Further objects and advantages of the present invention will become apparent and this invention will be better understood from the following description, refer ence being made to the accompanying drawing. The features of novelty which characterize the invention are set forth in the claims annexed to and forming part of this specification.

In the drawing:

FIG. 1 shows the front elevational view of the heating device embodying this invention;

FIG. 2 is a plan view, partly broken away, of the heating device shown in FIG. 1;

FIG. 3 is a sectional view taken along the line IIIHI in FIG. 1; and

FIG. 4 shows a sectional view similar to FIG. 3 of a modification of this invention.

Referring now to the accompanying drawing the heating device comprises a hollow box shaped heater body 1 containing a mixed gas conduit 2 having mixed gas suction ports 3 and 3' which are juxtaposed on the upper surface of the heating body in the transverse direction thereof. As shown in FIG. 3, the conduit 2 is communicated with these mixed gas suction ports 3 and 3 via a curved surface 2 having a hemielliptical configuration. The conduit 2 symmetrically extends in the opposite directions from suction ports 3 and 3' and the extensions of the conduit 2 are gradually bent towards a central mounting plate 4 which is secured on the front surface of the heater box 1 to form four mixed gas supply or exit ports 5, 5, 6 and 6' through the mounting plate 4. It is of course to be understood that the mixed gas suction ports 3 and 3' are connected to a suitable carburettor, not shown, and the exit ports 5, 6 and 6' to a four cycle internal combustion engine, in the embodiment illustrated. The space defined between the inside wall of the heater body 1 and the mixed gas conduit 2 thus serves as a passage for passing exhaust gas 7 with one end opened at the center of the mounting plate 4 between mixed gas exit ports 5 and 6, thus forming a pair of exhaust gas inlet ports 8 and 8, and with the other ends opened to provide another pair of exhaust gas inlet ports 9 and 9' on the outside of the mixed gas exit ports 5 and 6. Similar to the first pair of exhaust gas inlet 'ports the second pair of exhaust gas inlet ports extend through the front wall of the heater body 1 to terminate with mounting flanges and 10' which are flush with the central mounting plate 4. However, as shown in FIGS. 1 and 3 exhaust gas inlet ports 8, 8', 9 and 9' are positioned at a level lower than the mixed gas exit ports 5, 5', 6 and 6'. Further, as shown in FIGS. 2 and 3 the exhaust gas passage 7 is communicated with an exhaust gas discharge port 11 which extends through the bottom wall of the hollow heater body 1 just beneath the mixed gas suction ports 3 and 3. Thus, the exhaust gas inlet ports 8, 8', 9 and 9' are to be connected with the engine to receive therefrom exhaust 'gas while a muffler, not shown, may be connected to the exhaust gas discharge port 11, if desired. It is preferable to construct the exhaust gas passage 7 such that the sectional area thereof is largest at the inlet ports 8, 8', 9 and 9 and gradually decreased towards the discharge port 11, as shown in FIG. 2. Exhaust gas control members in the form of hollow tubes 12 and 12' are provided to extend in parallel across the exhaust gas passage 7 beneath the mixed gas conduit 2 and on the opposite sides of juxtaposed exhaust gas inlet ports 8 and 8'. These exhaust gas control members 12 and 12' not only serves as turbulators for the flow of exhaust gas to promote the thermal efficiency of the heating device, but also as convenient means for passing bolts through openings 13 thereof to secure the heater body 1 to the engine with its central mounting plate 4 and end flanges 10 and 10' abutting against the side Wall of the engine.

As can be noted from the foregoing description, in ac cordance with this invention all of the mixed gas supply openings 5, 5', 6 and 6 and exhaust gas inlet ports 8, 8', 9 and 9' are arranged to open in the front wall of the heater body 1, so that the heater body can be very readily mounted on the internal combustion engine. Moreover, these ports which are mounted on the front wall which directly receives heat from the engine are adequately heated not only by the exhaust gas but also by the heat from the engine with the result that the mixed gas or the mixture of fuel and air will be sufliciently heated while it travels through the conduit 2 from the suction ports 3 and 3' to the exit ports 5, 5', 6 and 6, thus assuring perfect combustion of the fuel, increase in the heat efiiciency, easiness of engine starting and saving of fuel consumption. This construction also permits use of cheaper kerosene. Moreover, according to this invention mixed gas suction ports 3 and 3 are located at the middle of the upper wall of the heater body 1 on the side remote from the front wall. As a consequence, as best shown in FIG. 3, the mixed gas conduit 2 is spaced from the front wall of the heater body 1 by the intermediate exhaust gas passage 7 so that there is no danger that the front side 2 of the mixed gas conduit -2 may be overheated by the heat from the engine but instead the conduit 2 and hence the mixed gas contained therein are heated uniformly. Moreover, as the exhaust gas inlet ports 8, 8', 9 and 9' are located below the mixed gas supply ports 5, 5, 6 and I 6, the exhaust gas coming directly from the exhaust gas inlet port 8 will impinge upon the bottom of the mixed gas conduit 2 to improve the thermal efficiency of heating because the mixed gas introduced from the suction ports 3 and 3' firstly contact with the inner side of that portion of the conduit. Further, in accordance with this invention,

as the exhaust gas inlet ports are opened to the front and as the exhaust gas discharge port 11 is opened to the bottom the exhaust gas will not flow through the shortest path as in the case where the discharge port is provided through the rear wall but instead the exhaust gas is given a sufficient opportunity to transmit heat to the mixed gas through the wall of the conduit 2. Further, the exhaust control members 12 and 12' traversing the exhaust gas passage 7 serve to adequately give turbulance to the flow of exhaust gas thus further increasing the thermal efliciency of heating. In the embodiment shown, two mixed gas suction ports 3 and 3 are provided so that one of them, for example 3 suctions the mixture of fuel and air at low speed running and at high speed running other port 3 also contributes to suction.

FIG. 4 shows a modified embodiment of this invention including a heating adjuster which is incorporated for the purpose of preventing excessive heating at the time of high speed running so that a larger output may be realized with more economical fuel consumption. In this modification a heating adjuster in the form of an external air suction valve 14 is connected to the rear wall 2 of the mixed gas conduit 2 at a point just beneath the suction ports 3 and 3'. As described above the mixed gas suction ports 3 and 3 are located adjacent to the rear wall of the heater body so that the front side wall 2" is remotely spaced from said front wall by the exhaust gas passage 7 while the spacing between the rear side wall 2" of the conduit 2 and the rear wall of the heater body is small. A tubular member 15 for mounting the air suction valve 14 extends through said narrow spacing to open into the conduit 2 just beneath the suction port 3' and at substantially the middle level of the heater body 1. As shown in the drawing the air suction valve 14 is secured to the cylindrical member 15 by threading thereto with a suitable packing 17 clamped therebetween. The suction valve 14 comprises a valve cylinder 18 having a valve seat 19 and an air vent opening 20, a movable valve 21, and a coil spring 22 which is interposed between an anchoring flange 23 and a head 24 at the outer end of the stem of the movable valve 21. Thus, the spring 22 functions to separate the movable valve 21 from the valve seat 19.

During low speed running the mixed gas is introduced in the conduit 2 through the suction port 3 which is located closer to the front wall of the heater body 1. As a result the negative pressure created in the conduit 2 permits the air suction valve 14 to close. However, during high speed operation the mixed gas will also be introduced through the other suction port 3' with the result that the pressure in the mixed gas coniduit 2 increases. Consequently, the air suction valve 14 is opened to introduce external cool air into the mixed gas conduit 2. Thus, the external air at room temperature effectively prevents excessive temperature rise in the conduit 2, thus maintaining the temperature in the conduit 2 at a substantially constant value. In addition, the introduced external air functions to increase the output of the mixed gas whereby to decrease fuel consumption for the same output. Since the external air is introduced into the mixed air conduit through the rear wall 2" thereof which is close to the valve mounting cylindrical member 16 and is maintained at a relatively lower temperature, the introduced air would got be heated to effectively cool the interior of the conuit 2.

While the invention has been explained by describing particular embodiments thereof, it will be apparent that improvements and modifications may be made without departing from the scope of the invention as defined in the appended claim.

What is claimed is:

1. A fuel heating device for internal combustion engines for motor cars and the like, said heating device comprising a hollow box shaped heater body, a mixed gas conduit contained in said heater body, a plurality of suction ports for said conduit which is opened through the upper wall of said heater body at the center portion thereof but at a position closer to the rear wall of said heater body, said suction ports being adapted to be connected to a carburetor to introduce mixed gas into said conduit, said conduit extending on both sides of said suction ports and being bent towards the front wall of said heater body, mixed gas outlet ports at the opposite ends of said conduit and extending through said front wall to supply said mixed gas to said engine which is adapted to be connected to said front wall, an exhaust gas passage extending in said heater body between the inner wall thereof and said mixed gas conduit, an exhaust gas inlet opening provided for said exhaust gas passage, said exhaust gas inlet opening extending through said front wall at a level below said mixed gas outlet ports, a discharge port for said exhaust gas passage extending through the bottom Wall of said heater body at a position just below said mixed gas suction port and an exhaust gas turbulence means in said exhaust gas passage, and, an external air suction valve means including a spring and a valve which is closed during low speed and opened during high speed by the spring, said spring being connected to the rear side wall of said mixed gas conduit on the side remote from said front wall of said heater body at a point beneath the suction port which is located closer to the rear wall of said heater body.

References Cited UNITED STATES PATENTS 1,256,738 2/1918 Smith 123122 1,379,437 5/ 1921 Bennett.

1,541,431 6/1925 Mason 123-122 1,641,619 9/1927 Breer 123122 1,660,609 2/1928 Fornaca 123122 1,670,550 5/1928 Putnam 123122 2,232,413 2/1941 Steskal 123l22 2,821,182 1/1958 Kennedy 123-122 AL LAWRENCE SMITH, Primary Examiner. 

